diff -r 4ebc2e2fb97c -r 71c04702a3d5 test/langtools/jdk/jshell/IdGeneratorTest.java
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/test/langtools/jdk/jshell/IdGeneratorTest.java	Tue Sep 12 19:03:39 2017 +0200
@@ -0,0 +1,126 @@
+/*
+ * Copyright (c) 2015, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/*
+ * @test
+ * @summary Test custom id generators
+ * @build KullaTesting TestingInputStream
+ * @run testng IdGeneratorTest
+ */
+
+import java.io.ByteArrayOutputStream;
+import java.io.PrintStream;
+import java.util.List;
+import java.util.function.Supplier;
+
+import jdk.jshell.EvalException;
+import jdk.jshell.JShell;
+import jdk.jshell.SnippetEvent;
+import jdk.jshell.UnresolvedReferenceException;
+import jdk.jshell.VarSnippet;
+import org.testng.annotations.Test;
+
+import static org.testng.Assert.assertEquals;
+import static org.testng.Assert.assertTrue;
+
+@Test
+public class IdGeneratorTest {
+
+    public JShell.Builder getBuilder() {
+        TestingInputStream inStream = new TestingInputStream();
+        ByteArrayOutputStream outStream = new ByteArrayOutputStream();
+        ByteArrayOutputStream errStream = new ByteArrayOutputStream();
+        return JShell.builder()
+                .in(inStream)
+                .out(new PrintStream(outStream))
+                .err(new PrintStream(errStream));
+    }
+
+    public void testTempNameGenerator() {
+        JShell.Builder builder = getBuilder().tempVariableNameGenerator(new Supplier<String>() {
+            int count = 0;
+
+            @Override
+            public String get() {
+                return "temp" + ++count;
+            }
+        });
+        try (JShell jShell = builder.build()) {
+            for (int i = 0; i < 3; ++i) {
+                VarSnippet v = (VarSnippet) jShell.eval("2 + " + (i + 1)).get(0).snippet();
+                assertEquals("temp" + (i + 1), v.name(), "Custom id: ");
+            }
+        }
+    }
+
+    public void testResetTempNameGenerator() {
+        JShell.Builder builder = getBuilder().tempVariableNameGenerator(() -> {
+            throw new AssertionError("Should not be called");
+        });
+        try (JShell jShell = builder.tempVariableNameGenerator(null).build()) {
+            jShell.eval("2 + 2");
+        }
+    }
+
+    public void testIdGenerator() {
+        JShell.Builder builder = getBuilder().idGenerator(((snippet, id) -> "custom" + id));
+        try (JShell jShell = builder.build()) {
+            List<SnippetEvent> eval = jShell.eval("int a, b;");
+            checkIds(eval);
+            checkIds(jShell.drop(eval.get(0).snippet()));
+        }
+    }
+
+    private void checkIds(List<SnippetEvent> events) {
+        for (SnippetEvent event : events) {
+            assertTrue(event.snippet().id().startsWith("custom"), "Not started with \"custom\": "
+                    + event.snippet().id());
+        }
+    }
+
+    public void testIdInException() {
+        JShell.Builder builder = getBuilder().idGenerator(((snippet, id) -> "custom" + id));
+        try (JShell jShell = builder.build()) {
+            EvalException evalException = (EvalException) jShell.eval("throw new Error();").get(0).exception();
+            for (StackTraceElement ste : evalException.getStackTrace()) {
+                assertTrue(ste.getFileName().startsWith("#custom"), "Not started with \"#custom\": "
+                        + ste.getFileName());
+            }
+            jShell.eval("void f() { g(); }");
+            UnresolvedReferenceException unresolvedException = (UnresolvedReferenceException) jShell.eval("f();").get(0).exception();
+            for (StackTraceElement ste : unresolvedException.getStackTrace()) {
+                assertTrue(ste.getFileName().startsWith("#custom"), "Not started with \"#custom\": "
+                        + ste.getFileName());
+            }
+        }
+    }
+
+    public void testResetIdGenerator() {
+        JShell.Builder builder = getBuilder().idGenerator((sn, id) -> {
+            throw new AssertionError("Should not be called");
+        });
+        try (JShell jShell = builder.idGenerator(null).build()) {
+            jShell.eval("2 + 2");
+        }
+    }
+}